chore(langchain_v1): clean anything uncertain (#32228)

Further clean up of namespace:

- Removed prompts (we'll re-add in a separate commit)
- Remove LocalFileStore until we can review whether all the
implementation details are necessary
- Remove message processing logic from memory (we'll figure out where to
expose it)
- Remove `Tool` primitive (should be sufficient to use `BaseTool` for
typing purposes)
- Remove utilities to create kv stores. Unclear if they've had much
usage outside MultiparentRetriever

.github/workflows/pr_lint.yml

@@ -81,6 +81,7 @@ jobs:
             core
             cli
             langchain
+            langchain_v1
             standard-tests
             text-splitters
             docs